Spoilers as to the identity of the Wicked Witch of the West contained within.

When I say that Oz the Great and Powerful is all downhill from the opening credits, don't take that to be too harsh a criticism. It's just that the opening credits are a delight; black-and-white and circus-y, with an old-timey charm that promises a game and cozy adventure to come. They're also, oddly, the film's best use of 3D, the images appearing rich and full-bodied without being intrusive or gimmicky. In a sad way, the credits hint at a movie that the director Sam Raimi could have made had the usual studio pressures not intervened, something small but richly detailed, a throwback picture gently and subtly enhanced by modern technologies. But, alas, it's not to be, as this is a computer fantasia created at the cost of hundreds of millions of dollars, an Oz where substance follows style and the impossible is realized all too easily.

That said, there is plenty to like in this prequel of sorts. The writers Mitchell Kapner and David Lindsay-Abaire have crafted an often witty script that tells the story of our titular hero's arrival in Oz with warmth and unexpected dollops of grace. There's an all-ages appeal to the writing that does not condescend to kids or showily wink with an overabundance of for-the-grownups irony, the way lots of supposedly clever "family films" do these days. Moments that are supposed to be scary are usually scary, while heartwarming lessons about goodness and kindness bear only faint whiffs of treacle. With one major narrative oopsy aside, which I'll get to in a bit, Oz the Great and Powerful is nimbly written, perhaps yet another tantalizing sign of what could have been had the 3D CGI green screen motion capture monster not gobbled the picture up.

But, gobble it does. After a brief introduction to Oz, a conman magician, in black-in-white turn-of-the-century Kansas, we are whisked off to the aggressively colorful, soullessly vivid land of Oz, full of precarious terrain, voluminous flora, and fantastical fauna. Oz's arrival in, uh, Oz is exciting enough, his hot air balloon swirling bracingly in the cyclone and then crashing down in roaring rapids, sending Oz toppling down vertiginous waterfalls before he has reached a deceptively calm shore. There Raimi takes his first opportunity to try and really dazzle us with the breadth and wonder of the special effects that a team of people on computers have created for him. And, sure, yeah, there's some cool-looking stuff, like a tree full of what look to be bright pink leaves but that turn out to be a flock of butterflies. But the minute the actors start to engage with the effects — swatting at a buzzing, sharp-toothed fairy creature or chatting with a winged monkey (voiced cutely by Zach Braff) — it all seems rather static and stagey. Now that we've learned how to use computers to create anything we could possibly dream up, it all seems rather weightless, doesn't it? When nothing's impossible, everything is less exciting.

It doesn't help that most of the actors in the film seem so uncomfortable with their synthesized surroundings. Oz is played by James Franco, an actor who is only good in theory as far as I'm concerned, and he brings the same smirking "Guys I'm not taking this that seriously" attitude to this project as he has to everything else he's done in recent years. (127 Hours excepted, I suppose.) He's so incongruous to the plucky story and cheery "scenery," largely by his own doing, that the magic glamour of all the expensive special effects seemed to fade from my eyes; it was as if I could see Franco wandering around some warehouse covered in green screen plastic. His own meta winking aside, I think Franco's just a bit too modern of voice and carriage to fit snugly into this quaint story. The same goes for Mila Kunis as Theodora, one of two witch sisters who have been eagerly awaiting Oz's prophesied arrival. Kunis suffers the most at the hand of Raimi's odd casting sensibility, and it's painful at times to watch her struggle so far out of her depth. Not that her character is terribly complex — she goes from lovelorn beauty to heartbroken green monster — but Kunis is simply too contemporary in look and voice to play well in this world. And she's too soft to be a mean old witch; her post-transformation delivery is all pained screams that read simply like a young and desperate actress trying in vain. Given a big task — reviving one of the most iconic villains in cinema history — the usually likable Kunis unfortunately tanks, taking much of the latter third of the film's energy with her.

Thank god then for Rachel Weisz, who plays Theodora's manipulative older sister Evanora. After twenty or so minutes of Kunis and Franco being the best kids in their high school play, it's a blessed relief to watch Weisz stride on screen and give the whole thing a shot of professional energy. It's clear from the get-go that she is secretly the wicked one all the people of Oz fear, and Weisz plays the slinking, sultry villain with elan. It's too bad, then, that ultimately her character arc proves rather flat. The movie's chief narrative stumble is to make the Wicked Witch of the West's wickedness be born out of nothing more than Theodora being upset over a boy. Weisz's Evanora has more pathos in one dark twinkle of her eye, and yet she just gets carted off at the end, sent to wait in obscurity for the day she's squished by a house. I guess the larger idea of making the Wicked Witch the initially kinder sister is a good one, but the execution is unimaginative; it feels sloppy and hurried. But, hey, why waste too much time working on telling a complex story when you can just make the witch a jealous girl and then go back to making all those cool computer pictures, right?

As Oz sets out to defeat the wicked witch, he makes friends with a little girl made of porcelain (she's from China Town, y'see), who is probably the most winningly animated presence in the movie. (She's voiced startlingly well by 13-year-old Joey King.) He also of course runs into Glinda the Good Witch, who is played with a nice sprinkle of daffy wit by Michelle Williams. (Who also appears as a hometown love in the Kansas sequence.) It's jarring to see Williams, such a low-to-the-ground indie presence in the years prior to this, navigating her way through CGI and leading attacks on magical castles, but she acquits herself better than one might think. Most importantly, she seems to be having fun, which lends her scenes some much needed vigor. She and Franco have a decent amount of chemistry, which they manage to maintain even as the siege story — the people of Oz vs. the witches of the Emerald City — becomes loud and cluttered. They sweetly bring the story to a close together, Raimi ending the picture on a nice cozy note similar to the beginning of the film.

Still, Oz the Great and Powerful, full of luminous but inert computer pictures as it is, mostly fails to enchant. The grand climax of the film is a sweet and clever nod to Oz's later smoke and mirrors routine — to scare the two evil witches, Oz rigs up some fireworks and a projection machine that makes him loom large and fiery. Of course it's all just an illusion, but in its deceptive simplicity, it manages to evoke big feelings. I wish I could say the same for the larger movie that houses it. Had I been Evanora or Theodora there on that final dais and Raimi had shown me his big digital light and noise show, I'm just not sure I'd have bought it. It's all very pretty in its own cold way, but very little of it made me say "Oh my."